Port 1121 is commonly used for remote console access to servers through the KVM (Keyboard, Video, and Mouse) over IP (Internet Protocol) protocol. It allows remote access to server hardware, even when the operating system is not responding or not yet installed. This port is also used for managing network-attached storage (NAS) devices.
Ports those registered with IANA are shown as official ports. The same port number may be unofficialy used by various services or applications. The official usage are listed separately below its usage may change from time to time.
Official
| Port | Protocol (TCP/UDP) | Title | Description | Port Type |
| Port 1121 | tcp | rmpp | Datalode RMPP | REGISTERED PORT |
| Port 1121 | udp | rmpp | Datalode RMPP | REGISTERED PORT |
UnOfficial
Unofficialy or sometimes with conflict, the same port may be used by different applications.
| Port | Protocol (TCP/UDP) | Description |